 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.cheatsheets.composite.model;

 import java.util.ArrayList ;
 import org.eclipse.ui.internal.cheatsheets.composite.parser.ITaskParseStrategy;
 import org.eclipse.ui.internal.cheatsheets.composite.parser.TaskGroupParseStrategy;
 import org.eclipse.ui.internal.provisional.cheatsheets.ICompositeCheatSheetTask;
 import org.eclipse.ui.internal.provisional.cheatsheets.ITaskGroup;

 public class TaskGroup extends AbstractTask implements ITaskGroup {
     
     public interface CompletionStrategy {
         public int computeState(TaskGroup taskGroup);
     }
     
     private ITaskParseStrategy parserStrategy;

     private ArrayList subtasks;
     
     private CompletionStrategy completionStrategy;

     public TaskGroup(CompositeCheatSheetModel model, String id, String name, String kind) {
         super(model, id, name, kind);
         if (kind == null) {
             this.kind = ITaskGroup.SET;
         }
         parserStrategy = new TaskGroupParseStrategy();
         completionStrategy = determineCompletionStrategy(kind);
     }

     private CompletionStrategy determineCompletionStrategy(String kind) {
         if (ITaskGroup.CHOICE.equals(kind)) {
             return new TaskChoiceCompletionStrategy();
         }
         return new TaskSetCompletionStrategy();
     }

     public ITaskParseStrategy getParserStrategy() {
         return parserStrategy;
     }
     
     public ICompositeCheatSheetTask[] getSubtasks() {
         if (subtasks==null) return EMPTY;
         return (ICompositeCheatSheetTask[])subtasks.toArray(new ICompositeCheatSheetTask[subtasks.size()]);
     }
     
     public void addSubtask(ICompositeCheatSheetTask task) {
         if (subtasks==null) {
             subtasks = new ArrayList ();
         }
         subtasks.add(task);
         ((AbstractTask)task).setParent(this);
     }
     
     /**
      * Called when the state of a child has changed or when the model
      * has been restored.
      */
     public void checkState() {
         int newState = computeState();
         if (newState != state) {
             setStateNoNotify(newState);
         }
     }

     /**
      * Determine the state based on the state of the children, which
      * will use a different computation depending on whether this is a set,
      * sequence or choice.
      */
     public int computeState() {
         return completionStrategy.computeState(this);
     }

 }

